Centrifugal blower wheel



April 28, 1959 E. LUNDE ET AL CENTEIFUGAL BLOWER WHEEL Filed March 1,1956 2 Sheets-Sheet 1 INVENTOR. E/NAR LUNDE BY WILLIAM T NICHOLS M vaway A TTOR NE VS April 28, 1959 Filed March 1, 1956 Pig. 5.

E. LUNDE ET AL CENTRIFUGAL BLOWER WHEEL 2 Sheets-Sheet 2 INVENTOR. E/NARLUNDE WILL/AM T NICHOLS ATTORNEYS U S at s P m;

CENTRIFUGAL BLOWER WHEEL Einar Lunde and William T. Nichols, La Crosse,Wis., assignors to The Trane Company, La Crosse, Wis., a

corporation of Wisconsin Application March 1, 1956, Serial No. 568,793

Claims. (Cl. 230-134) This invention relates to improvements incentrifugal blower wheels and more particularly to an improvedarrangement for assembling the cylindrical body structure of a blowerwheel to an associated hub plate.

Heretofore in the manufacture of centrifugal blower wheels, the processof assembling the large number of parts required for the complete wheelhas been a time consuming and expensive operation. The blade structureof this invention is such that the fan blades are assembled into aunitary flexible strip by the machine which forms the blades. By reasonof this construction, the number of parts required for ,a complete wheelis reduced and the assembly of the wheel is simplified.

-lt is an object of this invention to provide'a blade structure by whichthe blades are interlocked into a unitary flexible strip.

It is another object of the invention to provide a blade structure bywhich flanges on the blades form rim portions of the Wheel.

It is another object to provide a blower wheel which has a maximumeffective blade length with only a relatively small space at the endsfor blade retention.

It is still another object of the invention to provide a centrifugalblower Wheel in which the parts thereof can be assembled very rapidly sothat the wheels can be manufactured in quantities with low cost forlabor and material.

Other objects and advantages of the invention will become apparent asthe specification proceeds to describe the invention with reference tothe accompanying drawings in which:

Figure l is a sectional view of the blower wheel taken on line 11 ofFigure 5;

Figure 2 is an exploded perspective view of a portion of the blowerWheel showing the blade structure;

Figure 3 is an elevational end view of a blade before the interlockingtabs have been formed over;

Figure 4 is a partial side view of a blade with the interlocking tabscompletely formed;

Figure 5 is a sectional view of a single width wheel taken on line 55 ofFigure 1;

Figure 6 is a sectional view of a double width wheel taken on an axialplane;

Figure 7 is an elevational view of part of a wheel showing the weldsecuring the blades together at the end remote from the hub plate.

Referring now to the drawings and particularly Figures l and 2, numeral10 designates a hub plate to which is secured a hub 12 and blades 14.The blade 14 has a vane portion 16 which is arcuate or substantiallyarcuate in cross-section .and a flange base portion 18 at each endextending at right angles to the vane portion 16. Extending from theflange base portions 18 are flange end portions 20 offset outwardly fromthe flange base portions 18 so that the flange end portions 20 willreceive there'between the flange base portions 18 of the next adjacentblade. The shoulder 19 between the flange base portion and the flangeend portion has a radius of curvaice ture substantially the same as theconvex surface of the vane portion 16 of the blade.

The flange base portion 18 of each blade has a recessed outer edge 21and a recessed inner edge 22 both of circular form and having their axesof curvature substantially at the axis of curvature of the convexsurface of the vane portion 16 of the blade. The flange end portion 20of each blade has inwardly extending interlocking tabs 24 and 26 whichengage in the recessed outer edge 21 .and the recessed inner edge 22respectively of the flange base portion of the next adjacent blade tohold the blades in the form of a flexible strip leaving the bladeforming press. The interlocking tabs 24 of the first blade of a bladeassembly are not formed over but lie in the plane of the flange endportion 20 as shown in Figures 2 and 3. The interlocking tabs 24 .and 26of succeeding blades are formed over to lock the blade to the nextpreceding blade. In this manner the blade forming press interlocks therequired number of blades for the wheel.

A strip having the required number of blades 14 for agiven Wheel is thenplaced on a fixture having a cylindrical outer surface strip and thetabs 24 of the first blade are formed over against the recessed outeredges 21 of fixture with the inwardly extending bead 32 of the hub plateengaging the inner edge of one end of the blade assembly as shown inFigure 5. The blade assembly and the hub plate are then welded togetherby arc welding a bead 34 to join the end flanges of the blades 14 at oneend of the Wheel while simultaneously welding a bead 36 to join the endflanges of the blades 14 at the other end to each other and to the hubplate 10.

Figure 6 shows a double Width wheel. In making this wheel a hub plate 10is placed in the fixture and a blade assembly is placed in the fixtureon each side of the hub plate 10. A welding bead 38 is then produced atthe outer ends of the blade assembly to join the end flanges of theblades 14, and simultaneously therewith a welding head 40 is produced tojoin the inner end flanges of the blades to each other and to the hubplate 10.

It should be understood that although we prefer to use arc welding,other forms of welding may be used. For instance the end flanges of theblades may be secured to each other and to the hub plate by gas weldingor electric resistance welding or by solder dipping. It is alsocontemplated that the wheel assembly can be made by brazing the endflanges of the blades and the hub plate 10 to each other at their areasof contact. When the wheel is made of aluminum, the welds may be made bythe salt bath brazing process, and surfaces to be welded have a thincoating of an alloy having a lower melting temperature than the basemetal.

While We have described the foregoing preferred embodiments of ourinvention, we contemplate that many changes may be made withoutdeparting from the scope or spirit of our invention, and we desire to belimited only by the claims.

We claim:

1. A centrifugal blower wheel comprising a plurality of blades, each ofsaid blades having flanges thereon lying in planes which aresubstantially radial of said wheel, the flanges of the bladesoverlapping the flanges of the next adjacent blades, interlocking meanson the side edges of said flanges to hold the blades together. saidflanges being merged together in a weld to form wheel rims, and a hubplate welded to one of said wheel rims.

2. In a centrifugal blower wheel the combination of a plurality ofblades, each of said blades having a vane portion and flanges extendingfrom each end of the vane portion with said flanges lying in planeswhich are substantially normal to said vane portion, each of saidflanges having a base portion and an outwardly offset end portion, theoutwardly offset end portions of the flanges of each blade receivingtherebetween the base portions of the flanges of the next adjacentblade, said flanges having recesses in their side edges and tabsextending from their Side edges and extending into the recesses of theflanges of the next adjacent blade, means Welding said otfset endportions of the flanges to said base portions of the flanges receivedtherebetween to form continuous wheel rims.

3. In a centrifugal blower wheel the combination of a plurality ofblades, each of said blades having a vane portion and flanges extendingfrom each end of the vane portion with said flanges lying in planeswhich are substantially normal to said vane portion, each of saidflanges having a base portion and an outwardly oflset end portion, theoutwardly oflset end portions of the flanges of each blade receivingtherebetween the base portions of the flanges of the next adjacentblade, recesses in the edges of said flanges and tabs on the edges ofsaid flanges, said tabs extending into the recesses of the flanges ofthe next adjacent blade.

4. In a centrifugal blower wheel the combination of a plurality ofblades, each of said blades having a vane portion and flanges extendingfrom each end of the vane portion with said flanges lying in planeswhich are substantially normal to said vane portion, each of saidflanges having a base portion and an outwardly oflfset end portion, theoutwardly oflset end portions of the flanges of each blade receivingtherebetween the base portions of the flanges of the next adjacentblade, recesses in the edges of said flanges and tabs on the edges ofsaid flanges, said tabs extending into the recesses of the flanges ofthe next adjacent blade, means welding together the flanges at one endof the wheel, a hub plate abutting the other flanges of the blades andmeans Welding together the hub plate and said other flanges of theblades.

5. In a centrifugal blower wheel the combination of an annular row ofblades, each of said blades having a vane portion and flanges extendingfrom each end of the vane portion with the flanges lying in planessubstantially normal to said vane portion, each of said flanges having abase portion and an outwardly oflset end portion, the

outwardly offset end portions of the flanges of each blade receivingtherebetween the base portions of the flanges of the next adjacentblade, a continuous annular bead welded to the base portions and endportions of the flanges of the blades *at one end of the wheel, a hubplate abutting the other flanges of the blades, and means at theperiphery of said hub plate welding together the hub plate and saidother flanges of the blades.

References Cited in the file of this patent UNITED STATES PATENTS1,745,854 Lawaczeck Feb. 4, 1930 2,231,062 Evans Feb. 11, 1941 2,458,041Wessel Jan. 4, 1949 2,632,397 Jandasek Mar. 24, 1953 FOREIGN PATENTS267,405 Great Britain Mar. 17, 1927 339,565 Germany July 29, 1921

